A convicted sex offender has been arrested for allegedly molesting two sisters, aged 13 and 15, after breaking into their home and threatening them.

Rithy Mam, 33, who was previously found guilty of child stalking, had removed his GPS ankle monitor in September before entering the girls' home in Stockton, California. He was later arrested in a public park and is now in custody on felony child molestation charges.

Mam committed the crime after being arrested three times in two months last year on similar accusations. However, he was later released because California's legislation on parolees has been relaxed due to overcrowding in prisons.

Beating the system: Convicted sex offender Rithy Mam broke off his GPS device and allegedly molested two sisters in Stockton, California before being rearrested

He is one of thousands of child molesters and rapists
on parole who are getting away with new crimes after disabling their GPS
trackers because they no longer fear lengthy jail time, recent figures
have shown.

In the past 18 months, there have been 3,400
arrest warrants in California, mostly for known sex offenders, after it
was decided that parole violators should be put in county jail and not
state prisons which are bursting to capacity.

Although
the study is based solely on California prison statistics, across the
U.S. federal prisons are faced with the constant pressure of
overcrowding, suggesting that similar measures could be introduced
elsewhere.

America's prison system is at breaking point - with overcrowding in the nation's jails at its highest for eight years in 2012.

There are currently more than two million Americans behind bars. The worst hit state is California which houses 140,000 inmates when its 33 adult prisons are only designed to hold a maximum of 80,000.

Repeat offender: Fidel Tafoya, 48, was charged with sexual battery for assaulting a female student at Fresno State University last year. He had been released twice earlier in 2012 on similar accusations

Jack Wallace, from the California Sex Offender Management Board, told the LA Times this week that with little to stop them, 'parolees certainly are feeling more bold'.

California law requires that sex offenders wear a GPS device for
life - however there have already been horrifying breaches of the
system.

According to the current wanted list
posted online by the California Department of Corrections and
Rehabilitation, there are dozens of offenders who have violated the
conditions of their parole by tampering with GPS monitors.

Alarms go off when snapped, smashed or when a sex offender gets too close to a school or playground.

In Fresno County, 42 sex offenders broke parole in the last 18 months. In one incident, sex offender Fidel Tafoya, 48, was arrested on a college campus for assaulting a female student in the library.

Little threat: Now that California is no longer placing parole violators in state prison, many no longer have prison time to fear and are cutting off GPS ankle monitors (stock picture)

He was arrested on November 14 last year but had been released twice in 2012 on similar allegations. The repeat offender remains in custody charged with sexual battery to which he has pleaded not guilty.

Proposals have been put forward by lawmakers that would require parolees who damage their GPS bracelets to go back to jail for three years.

However critics, point to the fact that there are simply no cells in the prison system to hold these offenders.